DA BRITISH COPEPODA. 
similar size; in the male the fifth pair of feet (fig. 14) 
is rather smaller, and consists of two tapering laminge 
which are closely united almost to the apices, each of 
which bears two nearly equal spines, the external 
margins each having two slender sete; the first male 
abdominal segment (fig. 15) has attached to it a pair 
of small bisetose appendages, much like rudimentary 
feet. Caudal segments (fig. 16) subconical, a little 
longer than the last abdominal ring; tail setze two, the 
innermost much the longer, stout and finely aculeate 
along the margins, somewhat shorter than the abdo- 
men, but about five times as long as the outer one. 
The animal is of a deep brown colour, and is #5th of 
an inch in length (‘65 mm.). 
The only specimens of this species which I have 
seen occurred in a tow-net gathering made by my 
friend, Mr. EH. C. Davison, m Kinsale Harbour, 
Jreland, during the cruise of the “‘ Porcupine;”’ there 
were several examples, but, except one or two, all were 
males. The type-specimens described by Dr. Claus 
were taken at Heligoland, these two localities being at 
present the only recorded habitats of the species. 
Genus 7. RoBERTSONIA, nov. gen. 
Abdomen separated by a distinct constriction from 
the cephalothorax; anterior antennz short, 7- or 8- 
jointed ; inner branch of posterior antenne of moderate 
size, biarticulate; mandible-palp composed of a large 
